Spatial memory and learning in C57BL/6 mice- Effects of handling and optical modulation of hippocampal OLM-cells
Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
Background: This study is divided in two parts which both include different aspects of spatial memory and learning in C57BL/6 mice. Part I explores how handling of C57BL/6 mice prior to radial arm maze (RAM) test affect the memory performance. Part II further investigates spatial memory and learning focused on specific inhibitory interneurons in hippocampus called OLM (oriens laconosum moleculare) cells important for memory formation. In a small pilot study using Chrna2-Cre mice the OLM-cells were activated using optogenetics to prevent formation of spatial memories in the maze. Materials and methods: Part I: One group of animals was subjected to a predetermined handling protocol two weeks prior habituation to the RAM. The control group wasn’t handled at all prior habituation. The habituation phase consisted of 15 minutes daily exploration of the RAM for five days followed by ten days of testing with 10 minutes daily exploration. Part II: Five Chrna2-Cre positive mice, and three control animals were used in the RAM according to the same protocol as in Part I. When entering a rewarded arm the OLM cells were activated with blue light. Results: Part I: Handling of animals prior to the RAM test resulted in lower rates of reference memory errors entry into not baited arm, lower velocity and distance moved in the maze compared to not handled control animals. Part II: The activation of OLM cells didn’t show any significant differences between Chrna2-Cre positive and control animals. However there was a trend showing that the Chrna2-Cre animals didn’t show a decreasing number of reference memory errors over time as seen for control animals. Conclusions: Handling of mice prior to the RAM test resulted in better memory performance compared with control animals. Activation of OLM cells resulted in a trend showing that memory performance was decreased compared to control animals.
Place, publisher, year, edition, pages
2016. , 30 p.
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:uu:diva-275732OAI: oai:DiVA.org:uu-275732DiVA: diva2:900775
Master of Science Programme in Pharmacy
Ekmark Lewén, SaraSiwani, Samer